Just an update. I found a bunch of wires beside the oil tank on the left hand side.......It is a thick bunch of wires that are zip tied to the frame. ....I could unwrap the wires and cut away the wrapping and water poured out. The wires are all tied together in their colours and wrapped in a silicone sleeve that is supposed to be sealed. Well the earth wires were not sealed and the terminals were corroded.

I reckon a worthwhile follow up would be ensuring all connectors are sound and properly
installed AND some DiElectric Grease to insulate and act as preventative maintenance.